Search for resonances in electron-positron scattering using a cold positron gas target

The recently discovered correlated positron-electron peaks emitted from superheavy nuclear collisions may be signatures for previously undetected neutral particle-like objects having masses of 1-2 MeV/c2. The authors have designed an experiment to definitively test this hypothesis by searching for resonant states formed directly in the scattering of monoenergetic electrons incident on a gas of cold positrons confined in a Malmberg-type Penning trap. This technique will provide an improvement in sensitivity for detecting new neutral particle-like objects of two orders of magnitude over that of present positron-beam, thin-foil scattering experiments, which are fundamentally limited by the momentum of the atomic electrons. Combined with a recoil-shadow technique, this experiment will explore the entire four decade range in possible neutral particles lifetimes (10-3s to 10-9s) which cannot be probed by other methods